Internal grinding machines



March 12, 1957 A. F. TOWNSEND ETAL 2,784,534

INTERNAL GRINDING MACHINES Filed July 20, 1953 5 Sheets-Sheet lINVENTORS ALMON F To WNSEND L BLOOD B IAROLD March 12, 1957 A. F.TOWNSEND ETAL 2,784,534

INTERNAL GRINDING MACHINES Filed July 20. 1953 5 Sheets-Sheet 2INVENTORS ALMON F. TOWNSEND HAROLD L.BLOO0 A TTm March 12, 1957 A. F.TOWNSEND HAL 2,784,534

INTERNAL GRINDING MACHINES Filed July 20, 1953 5 Sheets-Sheet 3INVENTORS ALMON FTOW/VSE/VD BY HAROLD L. BLOOD March 12, 1957 A. F.TOWNSEND ETAL ,7

INTERNAL GRINDING MACHINES Filed July 20, 1953 5 Sheets-Sheet 4 FIG/0 INVENTDRS ALMON F TOWNSEND HAROL D L. BLOOD March 12, 1957 A. F. TOWNSENDEI'AL INTERNAL GRINDING MACHINES 5 Sheets-Sheet 5 Filed July 20, 1953lNVE/VTORS ALMON F. TOWNSEND HAROLD L BLOO B M United States PatentINTERNAL GRINDING MACHINES Almon F. Townsend and Harold L. Blood,Worcester, Mass., assignors, by mesne assignments, to The Heald MachineCompany, a corporation of Delaware Application July 20, 1953, Serial No.368,912

23 Claims. (Cl. 51-103) This invention relates to internal grindingmachines of the centerless or chuckless type in which workpieces areguided by their preformed outer surfaces of revolution while beingrotated and a rotating tool is applied to refine internal surfaces ofrevolution in the workpieces. More particularly, this comprisesimprovements for certain purposes in machines of this type disclosed inthe Blood application, Serial No. 242,102, filed August 16, 1951, nowPatent No. 2,646,652, dated July 28, 1953.

It is desirable to refine one or more inner surfaces of a roundworkpiece so that the finished inner surface has a predeterminedconcentric relation with an outer surface of revolution and in somecases without any particularly accurate relation with respect to the endfaces of the workpiece. In fact, many workpieces have end faces whichare out of square with respect to their axes of revolution and thereforesuch a workpiece cannot be supported with its end face against a backplate whose abutting face re-' mains square to the axis of revolution ofthe workpiece. Nevertheless, in the supporting and rotating of aworkpiece being finished, it is desirable to drive it and also tomaintain its position in an endwise direction by contact of a memberwith one or more of its end faces while accurately maintaining its axisof rotation so that its internal surface may be finished with respectthereto, by supporting it in means in contact with its outer surface ofrevolution which eliminates inaccuracies due to irregularities in theouter surface portion and variations in outside diameter as betweensuccessive workpieces. It is also desirable to provide support means incontact with the said outer surface which is axially long enough,particularly for supporting long workpieces, i. e., having a lengthgreater than the diameter, so that the workpiece rotates on a fixedaccurately predetermined axis.

Accordingly this invention provides means for internal-' ly grindingwork of such proportions that its axis of rotation may be fixed by fixedconcave supports engaging the periphery, and its endwise location may befixed accurately by a plate engaging a finished face of the work, eventhough the face is not quite at right angles to the periphery; alsomeans for internally grinding annular work in which concentricity of theground surface with the preformed periphery is more important thansquareness of the ground surface with a face of the work, assuming theface is not perfectly square with the periphery; also improved means forcontrolling the speed of rotation of work subjected to heavy cuts, whilekeeping distortion of the work at a minimum.

These and other features and objectives will become apparent from thefollowing description of the invention and from the drawings in which:

Fig. l is a longitudinal section through one embodiment of theinvention.

Fig. 2 is an end view of Fig. 1.

Fig. 3 is a section taken along the lines 33 in Fig. 1.

Fig. 4 is a longitudinal section through another embodiment.

Fig. 5 is a section taken on the lines 5-5 of Fig. 4.

2,784,534 Patented Mar. 12, 1957 Fig. 6 is an end view of anotherembodiment looking along the axis of the workpiece.

Fig. 7 is a top plan View of the embodiment of Fig. 6.

Fig. 8 is a sectional view taken along the lines 8-8 of Fig. 7.

Fig. 9 is a partial longitudinal view of a still further embodiment.

Fig. 10 is an end view taken along the lines 10-10 of Fig. 9.

Fig. 11 is a longitudinal view partly in section of a furthermodification.

Fig. 12 is an end view of Fig. 11 taken on lines 12--12.

Fig. 13 is an end view' of a modified work support. Fig. 14 is a View ofFig. 13 on lines 1414.

In the drawings, Fig. 1 shows a mechanism for grinding inner surfaces 1and 2 of a long workpiece 10 including a grinding tool 12 on a spindle113. The workpiece 10 is longer than its diameter and has an outercylindrical surface 3 and an end surface 4 which is out of square withrespect to the axis of the surface 3, this being exaggerated in thedrawings for illustrative purposes. The workpiece is supported by worksupport means comprising a pair of fixed work supports 15 and 16, eachhaving a pair of concave support surfaces 18 and 19 substantiallyconforming to the peripheral surface 3 of the workpiece and straddling aline L which is normal to the line F of feed of the wheel 12 into thework 10, thereby minimizing errors due to irregularities and variationsin size of the outer surface 3 at the line of contact C between thewheel and the work, as seen in Fig. 2. Since the work is supported onthe two supports 15 and 16, its axis of revolution is fixed. In order tomaintain the workpiece in an endwise direction and to rotate it while itis being ground, a magnetic wobble plate 20 is provided to be rotated bya pulley driven from any convenient power source not shown, and towobble: about its axis of rotation, i. e. rotate out of square to theaxis, so that it can maintain a continuous all around abutting contactwith the out-of-square end face 4 of the workpiece. For this purpose, asemi-spherical ball joint 21 integral with the wobble plate 20 isreceived in a corresponding semispherical concave bearing surface 22 inan enlarged end portion 23 of a magnetizable spindle 24 suitablysupported by a bearing 26 in a work head 27 and on the outside end ofwhich is mounted the pulley 25. The wobble plate 20 is also connected tobe driven by the enlarged spindle end portion 23 by a pair of resilientreeds 30, also seen in Fig. 3. The reeds 30, being arranged between thespindle portion 23 and the plate 20 in a direction tangential to theirrotation, are sufficiently rigid to transfer the torque and at the sametime sufficiently flexible to allow the plate 20 to wobble freely withinpractical limits in any direction around the ball joint from a planenormal to the axis of the workpiece. Mounted on the spindle 24 behindits enlarged end por tion 23 is a non-magnetic collar 31, which may beof bronze or similar material, which acts as a magnetic separator.Behind the separator 31 is a magnetic coil 35 surrounding the spindle 24and energized by wires 36 and 37 connected to a suitable power source38. A pair of switches 40 and 41 are connected in the lines 36 and 37respectively and the wires 36 and 37 are cross connected around theswitches 40 and 41 by resistances 42 and 43 and wires 44 and 45respectively.

A resiliently loaded pressure roll mounted on an arm 51 on a rock shaft52 is urged downwardly by suitable spring means (not shown) to urge theworkpiece, particularly its outer end, down against work supports 15 and16. The roll 50 may also be skewed as seen in Fig. 1 to supplement theforce exerted by the mag netized wobble plate 20 urging the workpieceagainst the wobble plate.

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Also connected to the rock shaft 52 is an ejector 55 having an operativeend 56 which raises between the work support elements 18 and 19 againstthe workpiece to eject it from operative position after the refiningoperation is completed. For this purpose, the rock shaft 52 is rotatedby suitable means (not shown) which also withdraws the pressure roll 56from the workpiece so that it may be ejected by the ejector 55.

During the grinding operation the switches 40 and 41 are closed, therebyenergizing the magnetic coil 35 and the wobble plate 26), holding theworkpiece against the wobble plate v so that it may be driven by thewobble plate. The switches 40 and 41 are held closed by the ejector 55in its downward position, as seen in Fig. 1, but when the rock shaft 52is rotated clockwise, as seen in Fig. 2, to withdraw the roll 50 andraise the ejector 55 against the workpiece, the switches 40 and 41 areallowed to open, thus demagnetizing the coil and the wobble plate 20.When the switches and 41 are open, current flows across the Wires, 44and and the resistances 42 and 43 tending to reverse the field in themagnet coil 35 and further demagnetizing the wobble plate 20.

With certain shapes and types of workpieces and the use of asufiicicntly strong magnetizing force, the pressure roll may bedispensed with. In such case it is preferable to mount the axis of thewobble plate 20 and its spindle 24 slightly off center with respect tothe axis of rotation of the workpiece 10, thus providing a slidingfrictional. engagement between the face of the Wobble plate and the endface 4 of the workpiece 10, creating a downward force urging theworkpiece against the work supports 15 and 16. In other instances, itmay be desirable to guide the workpiece 10 by power means applied to theroll 50 instead of to the wobble plate 20. During grinding the tool 12is rotated and fed relatively toward the work 10 by any conventionalmeans not shown.

Another embodiment of the invention is shown in Figs. 4 and 5, showing atool spindle 13a having two tools 12a and 12b for finishing internalsurfaces 1a and 1b of two workpieces 10a and 1011 which abut each otherat end surfaces 511 and 5b. The work may also comprise one piece havingan over-all length equal to the combined lengths of the two workpieces.The axis of rotation of the work is determined by a pair of worksupports 15a and 16a each having a support surface 1811. and 19a. Thesupport surface 180 straddles the line L1 which is normal to the line F1along which the tools 12a and 12b are fed into the work, and the supportsurface 19a is substantially in the line of feed F1, these two supportsurfaces thereby tending to eliminate errors due to irregulariites inthe peripheral surface 311 of the work with which they are in contactand providing support for the work against the force exerted by thetool. The end face 41) of the workpiece 10b abuts against a Wobble plate20a comprising a series of permanent magnets 28 circumferentiallyarranged with a loose fit in a non-magnetic separator 31a around theface of the wobble plate 20a with the end of the magnets 28 abuttingagainst the plate 20a. The Wobble plate 20a has a semispherical balljoint connection 21:: cooperating with a recess 22a in the enlarged end230 of a spindle 24a having a driving pulley 25a. A pair of reeds 30aresiliently connect the wobble plate 20a with the end 23a of the spindleso that the Wobble plate may be rotated to drive the work while at thesame time following the out-ofsquare end face 4b of the Work. Since themagnets 28 fit freely in the separator 31a, the latter being of adifferent material, is free to expand and contract independently of themagnets.

The spindle 24a is mounted in self-aligning bearings 26a and withadequate clearance 29 along its surface to allow the Wobble plate 20a tocenter itself with respect to the axis of rotation of the workpiece.

A second rotating wobble plate is resiliently urged against an endsurface 6 of the work thereby forcing the work against the wobble plate20a. The wobble plate 60 has a flange portion 61 received loosely in acircular chamber 62 formed by a casing 67 so that the wobble plate 60can move angularly with respect to the axis of rotation of the work andalsoradially in order to center itself with respect to said axis.

In operation, air under pressure is received from of the flange 61, asseen in Fig. 4, thus forcing the wobble plate 60 to the left against theWork. In this condition the air exhausts through a line 66. When thework is to be removed from the machine, the valve, 64 is reversedadmitting pressure through the line 66 retracting the wobble plate 60 tothe right away from the work. Thus, the force of the wobble plate 60supplements the magnetic force of the Wobble plate 20a to maintain theWork in driving engagement with the wobble plate 20a.

An adjustably positioned magnet 50, located between the work supports15a and 16a and adjacent but not touching the peripheral surface of thework, serves to urge the workpiece down onto the support surfaces 18aand also to increase the friction of the work on the supports thereby toprevent over-running of the work caused by the tangential force exertedby the tools 12a and 12b.

A further modification is shown in Figs. 6, 7 and 8 for grinding theinternal surface of a long workpiece 100. This machine includes agrinding tool 120 on a spindle 13c applicable to an inner surface of theworkpiece, two pairs of supports 15c and 160 each including arcuatesupport surfaces 18c and 19c straddling a line through the center of thework normal to the line of feed of the wheel into the work, a wobbleplate 200 and a pair of end rolls 70 and 71 resiliently bearing againstan end surface 60 of the work forcing its other end 40 against thebearing members 72 of hard metal inserted in the wobble plate 200. TheWobble plate 200 has a ball joint connection 21c with the enlarged and23c of a work drive spindle 24 which is mounted in conventional bearingsand driven by a pulley not shown. Also connecting the wobble plate 200so that it may be rotated by the spindle, are a plurality of screws 73and springs 74 providing resilient connections allowing the plate 20c towobble on the ball joint 210. An ejector 550, having an operative end560, is pivoted on a rock arm 52c.

The rolls 70 and 71 are independently mounted to operate in sequence andto be independently adjusted for various sizes of workpiece and forpressure exerted. The axis of the rolls may be displaced to the left asshown in Fig. 6 from the axis of the work so that as the work rotatesclockwise its contact with the rolls is part rolling and part sliding.

The sliding component is in an upward direction in the case of eachroll, which, therefore, exerts a downward force against end surface 60of the work, urging this end of the work against the pair of supports150. end of the work 40 is urged against the pair of supports 160 byplate 200 which is shown eccentric to the work. The roll 70 is mountedon an arm adjustably secured by screws 81 movable up and down in aT-s1ot 82 in an arm 83 pivoted by reed pivots 84 and 85 to a frameportion 86. The roll 71 is mounted on an arm adjustably secured byscrews 91 in a T-slot on an arm 93 pivoted to the frame portion 86 byreed pivots, indicated at 94 in Fig. 6, and similar to the reed pivots84 and 85. A spring 87 whose pressure is adjusted by a screw 88, urgesthe arm 83 in a clockwise direction to force the roll 70 against the endface 60 of the work and a spring 97, whose pressure is adjustable by ascrew 98, forces the roll 71 against the work. After the grindingoperation is completed, a fluid pressure operated cylinder operates Theother at 103 is a link 104 pivoted at 105 to the arm 93. Hence, movementof the link 101 to the left raises the ejector 550 to force the workfrom the machine and also moves the arm 93 counterclockwise, as viewedin Fig. 7, to retract the roll 71. As seen in Figs. 6 and 8, the arm 93has a portion 110 overhanging the arm 83 with a gap between. Thisprovides a lost motion so that the roll 71 is first retracted and thenthe overhanging portion 110 engages the arm 83 to retract the roll 70.This successive retraction of the rolls 70 and 71 facilitates workpieceloading because the roll 70, with less retraction, serves as a guide forinserting a new workpiece.

As best seen in Fig. 6, the center 'line or axis of rotation of therolls 70 and 71 is offset relative to the axis of the work thusproviding a component of force which urges the work downwardly againstthe support. The axis of rotation of the wobble plate 200 may also beoffset thereby providing a downward force on the work at its oppositeend. i

. Since the rolls 70 and 71 are able to follow an out-ofsquare end face60, the rolls are equivalent in function to the resiliently urging frontwobble plate 60 in Fig. 4.

Figs. 9 and 10 show an alternate form of wobble back plate d, anon-magnetized type, which may be substituted for other formsillustrated; for instance, the wobble plate 20a in Fig. 4. It pivots ona pin which connects it to an enlarged portion 23d of the spindle 24dallowing it to wobble in one plane. It has a pair of hardened workcontact elements 111 with which an outof-square surface 4d of theworkpiece 10d is adapted to make contact. As seen in Fig. 10, the workcontacts 111 are on a line normal to the axis of the pin 110 and, sincethe contact area is small, the line through the sur faces of thecontacts 111 in effect provides a pivotal axis normal to the pivotalaxis of the pin 110, so that the work contacts 111 may always be incontact at diametrically opposite points on an out-of-square work pieceend surface.

Figs. 11 and 12 show a modification of the invention for grinding, bymeans of a wheel 146 on a rotary spindle 148 carried by a conventionalwheelhead 149, the internal surface 1e of a workpiece 101:, such as aball bearing inner race, while the latter is supported on an externalsurface 3e comprising an outer ball groove having a circular arcuatesection. Since it is difficult to maintain accurately the axis ofrotation of a short workpiece by supporting it on such a surface, theworkpiece is held axially in alignment by urging its end face 4e, whichis first made square to its axis of rotation, against a rotating backplate having a spindle 124, the axis of which is fixed by supporting itin at least two sets of bearings 126 and 127. The driving face 128 ofthe back plate, against which the workpiece is urged, is therefore heldsquare to the desired axis of rotation of the workpiece. The workpieceis radially supported to fix its cent-er of rotation by a pair ofarcuate supports 130 and 131 whose surfaces, as seen at 132 in Fig. 11,have a rounded section conforming to the cross section ofthe supportsurface 3e of the workpiece.

The workpiece 10a is urged against the back plate 120 by a rotatingwobble plate which is free to wobble and to center itself radially in achamber 142 formed by a casing 147. The wobble plate 140 is urgedagainst the workpiece to force the latter against the back plate 120 byair pressure furnished by a pump 143 through a valve 144, theconstruction of the front wobble plate 140 and associated mechanism,shown in Fig. ll, being the same as that of the wobble plate 60 shown inFig. 4.

Figs. 13 and 14 show a modified form of support for use in the deviceshown in Figs. 11 and 12 in grinding a workpiece 10s. It comprises asupport member having a round support element 151 inserted thereinconforming to the round section of the outer race surface 3e of theworkpiece and the position of which may be adjusted by a set screw 152,and also a support member 155 having a shoe member 156 pivoted at 157,withapair of round support elements 160 and 161 inserted therein alsoconforming with the ball race surface 3e of the workpiece. The positionof the support member 155 may be adjusted by a set screw 165 and, sincethe support elements 160 and 161 are free to pivot around the pin 157,they maintain themselves in contact with the work surface 3e. Thesupport members 150 and 155 are arranged to straddle a line L throughthe center of the workpiece normal to the line of feed F of the wheelinto the work, and the support member 155 is positioned so that thesupport elements 160 and 161 support the workpiece substantially in theline of force exerted by the wheel against the Work.

In Figs. 11-14, the workpiece is urged radially against the supports130, 131 and 150, 160, 161 by a component of force exerted frictionallyby the backplate 128, which is mounted for this purpose slightlyeccentrically to the axis of rotation of the workpiece.

The wobble plates 60 (Fig. 4) and 140 (Fig. 11) have been described asbeing free to center themselves radially with respect to the axis of theworkpiece, but the work may be so located with respect to such a wobbleplate that the wobble plate will also urge the work against thesupports. This we prefer to do when the work is of such a nature thatother means for urging it against the support might be unsuitable orinadequate. For this purpose the casing 147, Fig. 11, may be locatedconcentric with spindle 120 which, as described and shown in Fig. 12, iseccentric to the workpiece 10e, also for this purpose. The radialclearance around the flange of the wobble plate 140 in the casing 147must then be small enough to keep the wobble plate from centering itselfwith the workpiece.

We claim:

1. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sufiiciently to bridge irregularities thereon and to positionthe workpiece radially, an end plate positioned to be abutted by one endof a workpiece on the support means, said end plate being rotatablysupported by means to allow it to wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpiece and being thereby capable of maintaining said abutting contactwhen said workpiece end is out of square with its axis withoutdisturbing the position of the workpiece on the support means, a magnetassociated with said end plate to provide frictional engagement betweenthe end plate and the workpiece, means to rotate the end plate therebyto drive the workpiece, a

grinding tool and means to apply the grinding tool to said innerworkpiece surface.

2. in an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sufficiently to bridge irregularities thereon and to positionthe workpiece radially, an end plate positioned to be abutted by one endof a workpiece on the support means, said end plate being rotatablysupported by means to allow it to wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpiece and being thereby capable of maintaining said abutting contactwhen said workpiece end is out of square with its axis withoutdisturbing the position of the workpiece on the support means, yieldablemeans to urge the workpiece against the end plate, said yieldable meanscomprising a pair of end rolls arranged to press against the other endof the workpiece, means to rotate the workpiece on said support means, agrinding 7 tool and means to apply the grinding tool to said innerworkpiece surface;

' 3. In an internalgrinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sufficiently tobridge irregularities thereon and to positionthe workpiece radially, an endplate positioned to be abutted by one endof a workpiece onthe support means, said end plate being rotatablysupported by means to allow it to wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpieceand being thereby capable of maintaining said abutting contact when saidworkpiece end is out of square with its axis without disturbing theposition of the workpiece on the support means, a yieldable rollarranged to make contact with said outer preformed surface to urge theworkpiece against the work support means, said yieldable roll beingskewed with its axis at an angle to the axis of the workpiece therebyexerting a component of force exerting the workpiece against theend'plate, means to rotate the workpiece on said support means, agrinding tool, and means to apply the grinding tool to said innerworkpiece surface.

4'. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece havingv an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sutficiently to bridge irregularities thereon, and to positionthe workpiece radially, an end plate positioned to be abutted by one endof a workpiece on the support means, said end plate being rotatablysupported by means to allow it to Wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpiece and being thereby capable of maintaining said abutting contactwhen said workpiece end is out of square with its axis withoutdisturbing the position of the workpiece on the support means, anonpermanent magnet associated with said end plate to provide frictionalengagement between the end plate and the workpiece, means to magnetizeand demagnetize said magnet, means to rotate the end plate thereby todrive the workpiece, a grinding tool and means to apply the grindingtool to said inner workpiece surface.

5. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outerpreformed surface and to extend circumferentially. in contacttherewith sufficiently to bridge irregularities thereon and to positionthe workpiece radially, an end plate positioned to be abutted by one endof a workpiece on the support means, said end plate being rotatablysupported by means allowing it to Wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpiece and being thereby capable of maintaining said abutting contactwhen said workpiece end is out of square with its axis withoutdisturbing the position of the workpiece on the support means, anonpermanent magnet associated with said end plate, means to magnetizeand demagnetize said magnet to provide frictional engagement between theend plate and the workpiece, meansto rotate the end plate thereby todrive the workpiece, a grinding tool, means to apply the grinding toolto said inner workpiece surface, an ejector for the workpiece, and meansoperable to demagnetize said magnet and then to actuate said ejector.

6. In an internal grinding machine for refining the inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution,

and in combination, fixed work support means havingan areuate concavesurface arranged substantially to conform with said outer preformedsurface and to extend circumferentially in contact therewithsufiiciently to bridge irregularities thereon and to position theworkpiece radially, an end plate positioned to be abutted by one endof-a workpiece on the support means, said end plate being rotatablysupported by means to allow it to wobble freely within limits from itsaxis of rotation while fixing it in a direction axially of saidworkpiece and being thereby capable of maintaining said abutting contactwhen said workpiece end is out of square withits axis without disturbingthe position of the workpiece on the support means, a magnet positionedto urge the workpiece against the support means, yieldable means to urgethe workpiece against the end plate, means to rotate the workpiece onsaid support means, a grinding tool, and means to apply the grindingtool to said inner workpiece surface.

7. In an internal grinding machine for refining the inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed Work support meanshaving an arcuate concave surface arranged substantially to con rotationand to fix it is a direction axially of said work-' piece, said endplate being thereby capable of maintaining said abutting contact whensaid workpiece end is out of square with its axis without disturbing theposition of the workpiece on the support means, yieldable means to urgethe workpiece against the end plate, means to rotate the spindle andthereby the workpiece, a grinding tool, and means to apply the rindingtool to said inner workpiece surface.

8. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sufficiently to bridge irregularities thereon and to positionthe workpiece radially, a rotatable spindle having a thrust bearin' anend plate rotated by the spindle, a flexible joint between the end plateand spindle holding the end plate rigid endwise of thespindle and freeto wobble relative to its axis so as to make continuous contact with anout-of-square end face of a workpiece in frictional abutting engagementagainst said end plate, said end plate being arranged to rotate about acenter eccentric to the work axis to rotate the workpiece and at thesame time to exert a component of force urging the workpiece onto saidwork support, means to drive the spindle and thereby the workpiece, agrinding tool and means to apply the grinding tool to said innerworkpiece surface.

9. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said machine including a centerless worksupport to position the workpiece radially on a support determined fixedaxis, a rotatable spindle having a thrust bearing, a back plate disposedtransversely to said axis in proximity to said work support means androtated by the spindle, a flexible joint having relatively movable partsbetween the back plate and the spindle holding the back plate rigidendwise of. the spindle and movable to wobble relative to the spindleaxis so as to make continuous contact with an out-ofsquare end face of aworkpiece on the support means and in frictional abutting engagementagainst said back plate, yieldable means to urge the workpiece againstthe back plate, meansto drive the spindle and thereby the workpiece,.aninternal grinding tool, a tool spindle substantially parallel tosaidfixed axis to support the tool, and means to move the tool spindleparallel and then transversely relative to the said rotatable spindle toapply the tool to a said inner workpiece surface.

10. In an internal grinding machine. for refiningan inner surface ofrevolution of a workpiece, said workpiece having an outer preformedsurface of revolution, and in combination, fixed work support meanshaving an arcuate concave surface arranged substantially to conform withsaid outer preformed surface and to extend circumferentially in contacttherewith sufficiently to bridge irregularities thereon and to positionthe workpiece radially on a support determined fixed axis, a rotatablespindle havingathrust bearing, a back plate disposed transversely tosaid axis in proximity to said work support means and rotated by thespindle, a flexible joint having relatively movable parts between theback plate and the spindle holding the back plate rigid endwise of thespindle and movable to wobble relative to the spindle axis so as to makecontinuous contact with an out-ofsquare end face of a workpiece on thesupport means and in frictional abutting engagement against said backplate, yieldable means to urge the workpiece against the back plate,means to drive the spindle and thereby the workpiece, an internalgrinding tool, a tool spindle substantially parallel to said fixed axisto support the tool, and means to move the tool spindle parallel andthen transversely relative to the said rotatable spindle to apply thetool to a said inner workpiece surface.

11. In an internal grinding machine for refining an inner surface ofrevolution of .a workpiece, said machine including a centerless worksupport to position a workpiece radially, an axially fixed rotatablespindle carrying axially immovably with respect thereto a back platedisposed with respect to the work support to make contact with'one endof a said workpiece on said support and to provide in cooperation withthe centerless support a substantially fixed support determined axis forsaid workpiece, said spindle and back plate being rotatable on an axiseccentric to said support determined axis so as to drive said workpieceand simultaneously to force it against the said support, means to rotatethe spindle, an axially yieldable front plate having a central aperture,means to carry the front plate generally coaxially with and transverselyto said support determined axis on the side of the centerless supportopposite said back plate thereby to make contact with the other end ofsaid workpiece, a flexible connection between said last named means andsaid front plate simultaneously providing rotary, axial, radial andwobbling movement of the front plate with respect to said supportdetermined axis, said wobbling movement being sufficient to allow thefront plate to make continuous parallel contact with an out-of-squareend face of a workpiece on the support means, means to urge the frontplate toward the back plate to clamp a workpiece between them, agrinding tool having a tool spindle substantially parallel to saidsupport determined axis, and means to introduce the grinding tool andtool spindle through said aperture and to apply the tool to a said innerworkpiece surface.

12. In the combination as set forth in claim 11, said flexibleconnection comprising a radial flange surrounding said front plate andforming a piston, and a circular pressure chamber carried by said meansto carry said front plate, said pressure chamber surrounding said backplate and flange with an excess of axial and radial clearance; and saidmeans to urge the front plate toward the back plate comprising fluidpressure means connected to said pressure chamber.

13. In the combination as set forth in claim 11, said centerless supportcomprising at least one surface relative to which a said workpiece isrotatably slidable and which is concave in a plane normal to the supportdetermined axis and convex in a plane containing the support determinedaxis and thereby arranged substantiallyto conform with a said outerpreformed surface which is concave in a plane containing the workpieceaxis.

14. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, and in combination, a centerless work supportincluding support surface portions arranged in circumferential spacedrelation thereby to provide radial support on a support determined fixedaxis for a workpiece being rotated with its external surface in contactwith said support, a rotatable spindle having a thrust bearing, a backplate disposed transversely to a said support determined axis inproximity to said work support and rotated by the spindle to makecontact with one end of a workpiece on the support, a flexible jointhaving relatively movable parts between the back plate and the spindleholding the back plate rigid endwise of the spindle and movable towobble relative to the spindle axis, an axially yieldable front platehaving a central aperture, means to carry the front plate generallycoaxially with and transversely to said support determined axis on theside of the centerless support opposite said back plate thereby to makecontact with the other end of a said workpiece, a flexible connectionbetween said last named means and said front plate simultaneouslyproviding rotary, axial, radial and wobbling movement of the front platewith respect to said support determined axis, said wobbling movementbeing sufficient to allow the front plate to make continuous parallelcontact with an out-of-square end face of a workpiece on the supportmeans, means to urge the front plate toward the back plate to clamp aworkpiece between them, means to drive said spindle to rotate a saidworkpiece, a grinding tool having a spindle substantially coaxial tosaid rotatable spindle, and means to introduce the grinding tool andspindle through said aperture and to apply the tool to a said innerworkpiece surface.

15. In the combination as set forth in claim 14, said centerless worksupport also including support surface portions which are axially spacedand separated from each other with respect to a said support determinedfixed axis providing a space therebetween and adjacent a workpieceseated in the support thereby arranged to make contact with axiallyseparated portions of a said workpiece.

16. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, and in combination, a centerless work supportincluding support surface portions arranged in both axial andcircumferential spaced relation thereby to provide radial support on asupport determined fixed axis for a workpiece being rotated with itsexternal surface in contact with said support, a rotatable spindlehaving a thrust bearing, a back plate disposed transversely to a saidsupport determined axis in proximity to said work support and rotated bythe spindle, a flexible joint having relatively movable parts betweenthe back plate and the spindle holding the back plate rigid endwise ofthe spindle and movable to wobble relative to the spindle axis so as tomake continuous contact with an out-of-square end face of a workpiece onthe support and in frictional abutting engagement against said backplate, yieldable rneans to urge the workpiece against the back plate,means to drive the spindle and thereby the workpiece, an internalgrinding tool, a tool spindle substantially parallel with the rotatablespindle, and means to move the grinding tool and spindle parallel andthen transversely relative to the spindle to apply the tool to a saidinner workpiece surface.

17. In the combination as set forth in claim 16, said end plate beingarranged to rotate about a center which is eccentric to the supportdetermined work axis to rotate the workpiece and at the same time toexert a compo- 1 1 nent ,of force urging the workpiece onto said worksupport.

18. In the combination as set forth in claim 16, sa d flexible jointincluding a ball, a socket receiving said ball, and resilient means tohold the ball in the socket and to prevent rotation of the back platerelative to the spindle thereby allowing the back plate to wobblerelative to the spindle while the spindle drives the back plate.

19. In the combination as set forth in claim 16, said means to urge theworkpiece against the back plate comprising a magnet associated with theback plate and disposed behind the operative face of the back platethereby operative to hold a said workpiece in frictional engagement withthe back plate.

20. In the combination as set forth in claim 16, said means to urge theworkpiece against the back plate comprising a pair of rolls arrangedwith respect to said work support to make contact with the opposite endof a said workpiece, and means to urge each of said rolls independentlyof the other against said workpiece whereby said rolls are capable offollowing an out-of-square said opposite end of said workpiece.

21. In the combination as set forth in claim 16, the support surfaceportions of said centerless work support being axially separated fromeach other providing a space therebetween and adjacent a workpieceseated in the support and thereby arranged to make contact with axiallyseparated portions of a said workpiece.

22. In the combination as set forth in claim 16, a magnet positioned insaid space between said axially separated support surface portions tourge a said workpiece against the centerless work support.

23. In an internal grinding machine for refining an inner surface ofrevolution of a workpiece, said machine including a centerless worksupport to position a workpiece radially, an axially fixed rotatablespindle carrying immovably with respect thereto a back plate disposedwith respect to the work support to make contact with one end of a saidworkpiece on said support and to provide in cooperation with thecenterless support a substantially fixed support determined axis forsaid workpiece, said spindle and said back plate being rotatable 12 onan axis eccentric to said support determined'axis so as to force saidworkpiece against said support, an axially yieldable front plate havinga central aperture,

'means to carry the front plate generally coaxially with andtransversely to said support determined axis on the side of thecenterless support" opposite said back plate thereby to make contactwith the other end of said workpiece, a flexible connection between saidlast named means and said front plate simultaneously providing rotary,axial, radial and wobbling movement of the front plate with respect tosaid support determined axis, said wobbling movement being sufitcient toallow the front plate to make continuous parallel contact with anoutof-square end face of a workpiece on the support means, means to urgethe front plate toward the back plate to clamp a workpiece between them,means to rotate one of said plates to drive the workpiece, a grindingtool having a tool spindle substantially parallel to said supportdetermined axis, and means to introduce the grinding tool and toolspindle through said aperture and to apply the tool to a said innerworkpiece surface.

References Cited in the file of this patent UNITED STATES PATENTS1,611,122 Mirfield Dec. 14, 1926 1,814,350 Theler July 14, 19311,843,079 Booth Jan. 26, 1932 1,938,763 Haas Dec. 12, 1933 1,999,320Dunham Apr. 30, 1935 2,039,223 Hutchinson Apr. 28, 1936 2,179,625 GrodenNov. 14, 1939 2,478,607 Theler Aug. 9, .1949 2,635,395 Arms Apr. 21,1953 2,646,652 Blood July '28, 1953 2,657,504 Cadman Nov. 3, 19532,706,369 Dix Apr. 19, 1955 2,715,304 Dix Aug. 16,1955 2,723,499 DixNov. 15, 1955 FOREIGN PATENTS 630,805 Germany June 6, 193 6.

